Functional states of kinetochores revealed by laser microsurgery and fluorescent speckle microscopy

View/ Open
Date
2011-10-26Author
LaFountain, James R.
Concept link
Cohan, Christopher S.
Concept link
Oldenbourg, Rudolf
Concept link
Metadata
Show full item recordCitable URI
https://hdl.handle.net/1912/4981As published
https://doi.org/10.1091/mbc.E11-06-0494DOI
10.1091/mbc.E11-06-0494Abstract
The impact of mechanical forces on kinetochore motility was investigated using laser microsurgery to detach kinetochores with associated chromatin (K fragment) from meiotic chromosomes in spermatocytes from the crane fly Nephrotoma suturalis. In spermatocytes, elastic tethers connect telomeres of homologues during anaphase A of meiosis I, thus preventing complete disjunction until mid- to late anaphase A. K fragments liberated from tethered arms moved at twice the normal velocity toward their connected poles. To assess functional states of detached and control kinetochores, we loaded cells with fluorescently labeled tubulin for fluorescent speckle microscopy on kinetochore microtubules. Control kinetochores added fluorescent speckles at the kinetochore during anaphase A, whereas kinetochores of K fragments generally did not. In cases in which speckles reappeared in K-fragment K fibers, speckles and K fragments moved poleward at similar velocities. Thus detached kinetochores convert from their normal polymerization (reverse pac-man) state to a different state, in which polymerization is not evident. We suggest that the converted state is “park,” in which kinetochores are anchored to plus ends of kinetochore microtubules that shorten exclusively at their polar ends.
Description
© The Author(s), 2011. This article is distributed under the terms of the Creative Commons Attribution License. The definitive version was published in Molecular Biology of the Cell 22 (2011): 4801-4808, doi:10.1091/mbc.E11-06-0494.
Collections
Suggested Citation
Molecular Biology of the Cell 22 (2011): 4801-4808The following license files are associated with this item: